PARIS — Until now, the Soviet Union hasn't had much success in tennis, although Alex Metreveli reached the Wimbledon final in 1973 and Olga Morozova did likewise in 1974.

Now, spurred by the fact that tennis will be an official sport in the 1988 Olympic Games, the Russians are making their move. This was demonstrated Saturday when Alexei Chesnokov stunned defending champion Mats Wilander, 6-2, 6-3, 6-2, to reach the fourth round of the French Open.

"When I started the match, I didn't even think of having chances," said Chesnokov, who is ranked 81st in the world. "But in every game and every set I thought more and more I had a chance."

Wilander had routed Chesnokov in their only previous meeting at Rome two weeks ago, but Chesnokov was too steady for the Swede this time.

"In Rome, it was only best-two-of-three sets and he didn't get that tired," the 20-year-old Chesnokov said. On Saturday, "you could see he wasn't moving as well as in Rome."

Wilander admitted he was all but helpless: "He just played a certain way, and I couldn't do anything. I felt the court was so small he seemed to be standing everywhere I put the ball. I felt every ball I hit was right at him."

Wilander, one of four Swedes seeded among the top seven players, was preceded out of the year's first Grand Slam tournament by No. 5 Stefan Edberg, No. 6 Joakim Nystrom and No. 7 Anders Jarryd.

Of the 12 Swedes who began the two-week tournament in men's singles, the only two left are Mikael Pernfors, a two-time NCAA champion at the University of Georgia, and Ulf Stenlund, who is playing in his first Nabisco Grand Prix event.

Both Lloyd and Wilander were defending champions seeded No. 2, and the implications weren't lost on Lloyd, who was seeking a record seventh French Open title, .

"I have to admit when I heard a lot of clapping I figured he (Wilander) had lost," Lloyd said. "I didn't want two major upsets in one day. He's also the second seed, and that went through my mind.

"I think she played an unbelievable first set," Lloyd said of her 16-year-old opponent. "She had me on the defensive. She mixed up the pace and played smart. She played aggressively.

"The second set, I just hoped to win a few games to get back in the match. Experience paid off for me."

There was other drama as well Saturday as eighth-seeded Henri Leconte of France fought off two match points in a third-set tiebreaker to beat Cassio Motta of Italy, 1-6, 3-6, 7-6, 6-0, 6-0.

In women's singles, third-seeded Steffi Graf and fifth-seeded Hana Mandlikova had identical 6-1, 6-3 victories, Graf defeating Pam Casale and Mandlikova beating Laura Gildemeister. Graf, who has a winning streak of 23 matches, will play Mandlikova in the quarterfinals.

Wimbledon champion Boris Becker was leading Eliot Teltscher, 6-3, 6-3, 5-7, when their match was suspended by darkness. If Teltscher should lose, that would leave South African-born Johan Kriek as the only American man to reach the Round of 16.